This invention relates generally to the field of dishwashing machines and more particularly to providing an improved unitary track for movably supporting a rack within the washing chamber.
In the design of front loading dishwashers it is common practice to provide at least two racks for supporting items to be washed. A lower rack is usually provided which will roll out onto the dishwasher door when the door is in the open posture. The upper rack is generally provided with some sort of rail or track mechanism which will support the rack while allowing it to extend out of the washing chamber for loading and unloading.
One track which has been disclosed in U.S. Pat. No. 3,472,573 utilizes a one-piece construction which includes two pairs of opposed curved beads. The rack rollers are captured between a first pair of beads and the tub rollers are captured between a second pair of beads. In this arrangement the rack and tub rollers are laterally offset from each other and the roller surfaces are shaped to conform to the curved bead surfaces.
Still another track is disclosed in U.S. Pat. No. 3,347,613 which includes a plurality of rollers mounted on the inside walls of the washing chamber with pairs of rollers spaced one above the other. An elliptically shaped track is secured to each side of the rack and the tracks are supported between the pairs of tub mounted rollers for movement of the rack-track assembly in and out of the washing chamber.
A track system for a desk or cabinet is disclosed in Belgium Pat. No. 561,719 which is of a one-piece construction but does not include flanges to totally retain the rollers mounted on the drawer or cabinet and does not show flanges formed by a double layer of sheet metal folded back on itself.